An air conditioning apparatus, which has two blowers and a single evaporator disposed at downstream of the two blowers, is known by US 2010/0248604. The air conditioning apparatus defines separated airflow passages for the respective blowers by using a separation wall. The separation wall contributes to avoid undesired reverse airflow directed into one of the blowers.
However, since the separation wall defines two airflow passages to the single evaporator core, if one of the blowers does not create enough airflow, a part of the evaporator core, which is disposed in the less airflow passage, may be frosted.
Therefore, even if passengers of the vehicle do not need high volume airflow, the air conditioning apparatus disclosed by the US2010/0248064 needs to keep running the two blowers together above a certain degree to prevent the evaporator from being frosted. To keep the both blowers running together ultimately will affect fuel consumption.
More specifically, the present disclosure provides a structure and a control method for an air conditioning apparatus, which has two blowers with a single evaporator core, and is able to operate with a single blower at minimum power consumption to prevent evaporator frosting and undesired reverse airflow.